The present disclosure relates to a sewing machine that is capable of sewing a circular shape by sewing a plurality of iterations of a single stitch pattern using a circular stitching device.
A circular stitching device for repeatedly sewing a selected stitch pattern around the circumference of a circle is known. When the circular stitching device is used, a user may, for example, anchor a single point on a cloth to a needle plate of a zigzag sewing machine by inserting a pin from above the cloth into one of a plurality of holes that are provided in the needle plate. A CPU of the sewing machine recognizes the distance from the anchored point to the center of a needle, that is, the radius of the circle, and computes the circumference based on the radius. Based on the circumference and on the length of the selected stitch pattern, the CPU computes revision data and the number of times that the stitch pattern, with its length revised, will be sewn, then stores the results. Based on the revision data, the CPU revises the length of the stitch pattern for the computed number of times that it will be sewn, then sews the stitch pattern, with its length revised, such that the point where the sewing ends matches the point where the sewing started.